Thanks for all the great insight - looks like I am not alone in my observations about the challenge of drafting in Zwift. Don’t get me wrong… I’m not complaining as the App is great, but did want to find out if there was a trick to drafting that I had not figured out yet.
I tried the advice of the earlier posts tonight and by being very careful to stay in the group, was able to ride the loop about 10% faster than without the group, while putting in the same effort. Curiously, the average watts for the ride went up ~10% but my heart rate was the same. This suggests that the App gave me “bonus watts” for riding in the group but the actual power coming out of my legs was ~10% less. Regardless of that theory, it does make sense to try and stay inside the pack.
To D. Tyler: It’s also my experience that riding in a pack is worth ~20% so your numbers of 220w to ~170 make sense. That is certainly not what we feel from the Zwift App.
To Craig H.: I hadn’t thought about the power effect of flats vs hills but if what you say is true that I wouldn’t stand a chance against most riders (my FTP is ~185 watts). Maybe I shouldn’t feel so bad when I get dropped going down a hill! :-)